Pixel shift technology has been used for some time, in particular in the digital camera sector, to obtain an improvement in resolution and image quality. The method is used for image stabilization, for resolution enhancement and for protecting the color information for sensors with color pixels. At present, there are also many applications in microscopy.
In pixel shift technology, as it is to be understood in the present application, the camera sensor is used to take two or more images in which the optical imaging of the object relative to the camera sensor is shifted by one pixel or less in the horizontal and/or vertical direction and is thus imaged on a slightly displaced region of the camera sensor. Either the camera sensor or an optical element can be actively moved. From the recorded individual images, a qualitatively better image is then calculated using known image processing methods.
JP 2012-163910 A discloses a microscope in which an image-shifting device for resolution enhancement is arranged in the optical path. This device shifts the optical imaging according to the settings of an actuator. A parallel plate glass with projections is inclined by a rotatable cam ring. The cam ring is driven by a motor. The production of the parallel plate glass with the projections is relatively costly. The positions of the projections firmly define the path of movement. As a more rapid alternative to the cam ring, the use of DMDs (digital micromirror devices) is proposed, their inclination adjusting the path of movement of the optical imaging. Various possibilities are covered by the term microscanning.
DE 69 528 915 T2 describes a pixel shift method for a camera, in which a mirror or a rotary prism is tilted to move the image or a lens group is moved vertically. In this method, it is possible to select the operating mode of the camera and therefore either an image stabilization or an enhanced resolution.
JP 2008 065 340 A discloses a microscope with two image-capturing devices at high speed and low speed and with an objective separate from the microscope. The objective is movable by means of a complicated mechanism using drives in order to calculate movements of the objective from the images. The movement of the entire objective can only take place relatively slowly.
JP 2012 163 616 discloses a zoom objective that uses pixel shift for image stabilization. The zoom objective comprises several lens groups, of which one is movable. A vibration detector detects vibrations of the zoom, and an actuator is controlled according to the vibrations in order to move a lens group perpendicularly with respect to the optical axis.
U.S. Pat. No. 6,397,008 B2 discloses a camera with an image stabilizer. The movement of the camera is established by means of acceleration sensors and, from this, the control of the actuator for the lens movement is determined. The lens is mounted resiliently at three points by means of slide bearings.